As costs increase for recovering diminishing supplies of conventional fossil fuels, and evidence mounts about the adverse environmental impact of burning those fuels, developing viable energy alternatives has become a national (and international) priority. One alternative fuel that is receiving considerable attention is hydrogen gas (H2). The byproducts of hydrogen combustion are energy and water, making hydrogen one of the cleanest fuels available for transportation, as well as the generation of electric power. The hydrogen may be harnessed for useful work with conventional power generating systems like steam turbine electric power generating systems and internal combustion engines for motor vehicles, but these systems all suffer from low electrical efficiencies due to the limitations of the Carnot cycle.
Hydrogen becomes more economically competitive with conventional fuels when used in systems with higher efficiencies, such as fuel cells. The costs of electrical power from a fuel cell utilizing hydrogen gas derived from natural gas (e.g., CH4) may be estimated with the following formula:
      Cost    kWhr    =            $      /      Mcf                      V        cell            ·              η        f            ·              (                  moles          ⁢                                          ⁢                                    H              2                        /            mole                    ⁢                                          ⁢                      CH            4                          )            ·      67.7      Where $/Mcf is the cost of natural gas per 1000 ft3, Vcell is the operating voltage of the cell, ηf is fuel utilization, and the ratio of moleH2/moleCH4 is the moles of H2 produced per mole of CH4 used. The factor of 67.7 in the denominator is for units conversion of volts times Mcf to kWhr.
FIG. 1 shows a graph of the cost of electrical power generated by a fuel cell as a function of the price of natural gas. For a natural gas price of $9.5/Mcf, the electrical power generated by the fuel cell is estimated to cost between $0.083/kWhr and $0.074/kWhr for utilization rates of 80% and 99%, respectively. When these costs are restated in terms of price per gallon of gasoline (assuming 70% fuel cell efficiency), the costs range between about $2.40/gal and $1.90/gal, which is very competitive with current gasoline prices, and expected to be more so in the future as gasoline costs continue to rise with rapidly increasing worldwide demand.
Thus, the efficiency gains realizable by hydrogen powered fuel cells can make them competitive with conventional transport and power generation technologies utilizing hydrocarbon based fuels if hydrogen can be manufactured cheaply enough. At the present, the most economical way to make hydrogen is by reforming or partial oxidation of fossil fuels, coal, and hydrocarbons not derived from fossil fuels, such as biofuels.
Building national and international distribution systems for hydrogen is conservatively estimated to take decades and cost hundreds of billions (if not trillions) of dollars. In addition, because hydrogen is much more leak-prone than any gaseous fuel currently in widespread use, unforeseen problems with developing a hydrogen distribution infrastructure will likely increase development times and drive up costs even further. These and other barriers to the widespread adoption of hydrogen for electrical power and vehicle fuel will make a hydrogen economy difficult to implement, even in an environment where conventional fuel costs are rapidly rising. Thus, there is a need for novel methods and systems to make hydrogen widely available without incurring the high costs of developing a hydrogen gas distribution infrastructure. These and other issues are addressed by the present invention.